A magnetic resonance imaging (hereinafter, referred to as “MRI”) apparatus, which is an example of a medical imaging apparatus, is an apparatus that measures a nuclear magnetic resonance (hereinafter, referred to as “NMR”) signal generated by an object, especially the spin of nuclei that form human tissue, and images the shapes or functions of the head, abdomen, limbs, and the like in a two-dimensional manner or in a three-dimensional manner. Different phase encoding and different frequency encoding are given to NMR signals by the gradient magnetic field, and the NMR signals are measured as time series data. The NMR signals are reconstructed as an image by a two-dimensional or three-dimensional Fourier transform. An operator sets a region to be imaged as an imaging slice through a GUI or the like. The imaging slice that the operator designates through a GUI or the like is converted into an imaging parameter, and the imaging of the imaging slice is performed. In addition, in this specification, an imaging region involving not only an imaging region at the time of single slice imaging but also a three-dimensional region at the time of multi-slice imaging is called an imaging slice hereinafter.
In an examination using an MRI apparatus, across-section that is anatomically determined is usually imaged for each part to be examined. This cross-section is called an examination section. In the examination, the operator sets this examination section as an imaging slice for each object. For example, in the case of medical checkup of the brain, as the examination section, there are planes along the reference lines, such as the OM (Orbit-Meatus) line or the AC-PC (Anterior Comisure-Posterior Comisure) line. For these reference lines, anatomical feature points are their references. An operator sets an imaging slice so as to pass through the feature point. In addition, as an examination using an MRI apparatus, there is a postoperative follow-up examination in which the same part of the same object is continuously imaged. In this case, the operator sets the same position of the object as an imaging slice in each examination.
The setting of an imaging slice is performed manually on scanogram images (scanogram images for positioning) in three directions that are acquired for positioning. However, depending on the part, the setting of an imaging slice should be performed in three-dimensional space. In addition, various conditions should be satisfied under various constraints. Therefore, the setting is difficult and requires skill. For this reason, the setting accuracy or the time taken for the setting differs depending on the operator. In particular, in a region (for example, a joint region) where the anatomical structure is complicated, the difference is large.
In order to solve the difficulty of imaging slice setting, a method of automating a part of the setting procedure has been proposed (for example, refer to NPL 1). NPL 1 discloses a technique of learning the pattern of an imaging slice setting executed by an operator and using it as slice plan setting information in the imaging slice setting. Here, on a 3D image obtained by performing 3D (three-dimensional) volume imaging, an imaging slice is calculated using the slice plan setting information.
In addition, there is a technique of automatically determining an imaging slice at the time of actual imaging on the basis of an imaging slice set in advance on a standard image (for example, refer to PTL 1).